// JavaScript Document

var parentId ;
var chords =  ["A", "A#", "B", "C", "C#", "D", "D#", "E", "F" , "F#", "G", "G#" ];
var chords2 =  ["A", "Bb", "B", "C", "Db", "D", "Eb", "E", "F" , "Gb", "G", "Ab" ];
var intval = 2;


function findIdx(val){
	for(i=0;i<chords.length;i++)
		if(val==chords[i] || val==chords2[i])
			return i;
	return -1;
}

function cal(val){
	var idx = findIdx(val);
	if(idx==-1) return "-";
	var nidx = idx+intval;
	var ret = chords[nidx%chords.length];
	
	return 	ret;
}

function updateIntval(_old,_new){
	var oldk = document.getElementById(_old).value;
	var newk = document.getElementById(_new).value;
	//alert(oldk + " " + newK);

	intval = findIdx(newk) - findIdx(oldk);
	if(intval<0) intval+=chords.length;
	transpose();
}

function transpose(){
	var parent = document.getElementById(parentId);
	
	var divs = parent.getElementsByTagName("div");

	for(ii=0;ii<divs.length;ii++){
		var div = divs[ii];
		var inputs = div.getElementsByTagName("input");
	
		var val = inputs[0].value;

		if(val=="") continue;
		var pos = 1;

		if(val.length>1 && (val.charAt(1)=='#' || val.charAt(1)=='b'))
				pos = 2;

		
		inputs[1].value = cal(val.substring(0,pos)) + val.substring(pos);
	}
//	alert(inputs[0].value);
//	alert(inputs[1].value);
	
}


function createField(){
	var parent = document.getElementById(parentId);
	var field = document.createElement("div");

	field.innerHTML = "<input type='text' size='8' />-&gt;<input type='text' size='8' />";		
	parent.appendChild(field);
	
}

function createFieldFirst(){
	var parent = document.getElementById(parentId);
	var field = document.createElement("div");

	field.innerHTML = "<input type='text' size='8' value='C' />-&gt;<input type='text' size='8' />";		
	parent.appendChild(field);
	
}